Still having problems with v3.3.2 I'm afraid, only now I'm getting "The page isn't redirecting properly - Firefox has detected that the server is redirecting the request for this address in a way that will never complete." On the Twitter site.

I just wanted to report that after I read someone's fix regarding the redirect loop error - which was the problem I was having - I was able to get an authorization and get the plug in working. So far so good! :)

This issue was because the wordpress site url had www in it and the url which was in admin dint had www or vice versa. the solution to this problem is before authenticating with twitter, just update your url in the tweet old post settings page and update the setting first then try to authenticate with twitter.